The term "Smart Grid" broadly describes emerging power systems whose physical operation is managed by significant intelligence. The cyber infrastructure providing this intelligence is composed of power electronics devices that regulate the flow of power in the physical portion of the grid. Distributed software is used to determine the appropriate settings for these devices. Failures in the operation of the Smart Grid can occur due to malfunctions in physical or cyber (hardware or software) components. This paper describes the use of fault injection in identifying failure scenarios for the Smart Grid. Software faults are injected to represent failures in the cyber infrastructure. Physical failures are concurrently represented, creating integrated cyber-physical failure scenarios that differentiate this work from related studies. The effect of these failure scenarios is studied in two cases: with and without fault detection in the distributed software. The paper concludes by utilizing the information gained to refine and improve the accuracy of the quantitative reliability model presented in our earlier work.